Train control



June 17, 1930.

w.' K. Howe:

TRAIN CONTROL Filed Oct. 29, 1924 .lune 17, 1930. w. KQ HowE v 1,765,334

TRAIN CONTROL Filed Oct. 29. 1924 4 Sheets-sheet 2 W. K. HOWE June 17, `1930.

TRAIN CONTROL 4 sheets-sheet Filed oct. 29|, 1924 l FIG:

lill

TTORNEY June 17, 1930.

w. K. HowE TRAIN CONTROL Filed Oct. 29, 1924 4 Sheets-Sheet the engineer.

Patented .linie 17, 1930 stares vpar rassen yri-*ica winrriiaor n. Howie, or' ROCHESTER, nnWYonK, assronon To GENERAL RAILWAY sronnncor/LPANY, or nocrinsrnn, NEW YORK VTRAN CONTROL y AApplication filed. October 29, 1924. Serial No. 746,578.

particularly to such systems of the so-called continuous inductive control type.

lGenerally stated, the system of this invention automatically applies the brakes at each caution sional or corresponding control point and prevents the release of the brakes until the train has been brought to a stop, unless takes suitable anticipatory action, conveniently called. acknowledgment. The engineer is also required to acknowledge neartlie exit end of the caution block, braking distance for the minimum speed from the stop f signal at the entrance to the next block in F w J block, the brakes advance. In accordance'with this invention,

the engineer is required to acknowledge each successive stop signal. Y Y

As the train travels through` a caution are automatically applied unless the speed of the train is reduced and atall times is within a curve-"of permissive speed limits, thereby assuring that the train ,m at all times can` be Stopped before reaching the ond ot the caution block. `For t Simmen, No. 1,150,308, dated Augustl?, v1915.-

his purpose brake control apparatus V'of the speeddistance type is preferably employed, such as illustrated, for example, in the patent to P. J.

ln the continuous inductive type of train control system, as ordinarily installed, the car relay deenergisedmomentarily at various points along the track, conveniently called dead sections,7 frequently found atfrogs, cross-overs,f staggered insulated joints, and

fie

similar locations, and it is proposed to use 'the distance element of the regular speedldistance type 0i" speed control apparatus to ypclffniit train movement over such dead-secytions without automatic brake applications or n' l brake control apparatus such that a minimum speed limit, or equivalent sate control, will be instantly and automatically set up in the event of such sudden danger, it being beyond the power of the engineer, by acknowledgment or otherwise, to prevent such minimum speed limit or avoid a brake application as the result of this speed limit.. p

In addition to the regulation of the speed of trainsv to enforce obedience to the indications ot' block signals, it is desirable to entorce an absolute .stop at certain points, such as at drawbridges, crossings, and the like.'v For this purpose it is desirable to have an indication or control from the trackway, in addition to those used for governing the trains in automatic block signal territory, and providefor an automatic unpreventable brake application, `occurring irrespective ofspeed, upon failure of such additional indication or control. In accordance with the present invention, it is proposed to maintain a signalling or train control current on the track rails throughout block signal territory, irrespective of traffic conditions, and to utilize cessation of such current at the interlocked signal or corresponding point of absolute stop to produce the 'desired brake application.

' yVarious other objects, advantages, and .characteristics features of the invention will be in part apparent and in part pointed out as the description progresses.

In describing the specific embodiment of the invention illustrated in detail reference will be made to the accompanying drawings in which Fig. l shows in a simplified and diagrammatic manner the trackway `equipment of an automatic train control system of this invention for automatic block signal territory, together with the impulse receiving equipment and main control relay on the car, speed-distance curves of permissive speed and train performance, and interrupted lines indicating the points ot opening and closing of certain contacts; f Y

Fig. 2 illustrates how the same track rwhich has been shown in Fig. l is modied and organized to provide for speed control and an absolute stop upon the approach to an interlocked signal; Y

in eiiect a wiring diagram of the car-carried apparatus and Fig. 5 illustrates a modiiied kform ofthe trackivay equipment for block siOnal system territory and for the approach to an'interlocked signal, together With curves and interrupted lines, similar to those shown in Figs. 1 and 2. v

Tmccwcy equipment-Figs 1 shows the usual type of control circuits and devices for a continuous inductive control system of the three-position type having direct current track circuits. The track rails 1 are divided into blocks by insulating joints 2 in the usual Way, one complete block I and the adjacent ends of tWo other blocks H andv J being shown. For simplicity it is assumed that the length of these blocks correspondsfto braking distance and includes only one track circuit, various expedients (not shown) being employed to adapt the system torblocks of various lengths and those including cut sections. It is also assumed that all of the blocks'will be equipped the same, so that a description ot one Will sutlce for all.'

Using the reference numbers o'l' the block l,

each block is provided with a normally closed direct current track circuit, including a track battery 3 andl a track relay 5. Thel track phase or loop circuit current for they train control system, Which lows in opposite directi ons in the track rails at a given instant, is impressed across the track rails at the exit end of each block by a transformer 4, Ahaving its secondary in series With the track battery 3, and its primary continuously energized from a line transformer 6 connected to the usual transmission line T. The line phase or simplex circuit current, AWhich flows in the same direction in the two track rails at a given instant, is supplied to the track rails of each block through balancing resistances 'T land 8 across track rails at the ends of the block, the middlel points of these resistances being connected by line Wires 9 and 10 to contact fingers 111 and 121 of the track relay 51 ot the'neXt block in advance and through pole-changing contacts 11l and 121 to the sec ondary of a line transformer 131. The line vphase and track phase currents are displaced in phase in the usual Way. f

l/Vhile the present train control system may be used With or Without Wayside signals as desired, semaphore signals Z have been shown conventionally Without attempting to illustrate their Well known control circuits and devices.

lligure 2 shows the trackway equipment for a block K neXt in the rear ot an absolute stop and stay signal, ZA, which is assumed to be controlled manually from a tower by an interlocked lever in the usual Way, With such locking and Well recognized expediente as may be found desirable. In this block KV of absolute stop control, an additional balancing resistance 14; is connected across the track rails a short distance from the exit end thereof; and provision is made so that, With the stop and stay signal ZA in the stop posi'- tion, the line phase 0r simplex current is supplied between the balancing resistance 72 at the entrance to the block K and the balancing resistance 1A only, there being no line phase or siniplex'circuit current for the short distance at the exit end of the block.y In the simplilied form of the invention illustrated, a switch 15, assumed to'be connected to or operated by an interlocked lever or equivalent means, is used to control the connection of the line phase circuit to the resistances 14 and 82. lvl/'hen the signal ZA is at stop, it is desirable to enforce restricted speed limits upon its approach; and as shown, this is accomplished by pole changing contacts 16 on the signal ZA controlling-the line phase current.

Uar'egm'gament.-The receiving devices for f detecting and amplifyingv they train control current in thetrack rails are, generally speaking, of the usual type and construction. vReferring to Fig. 1, the locomotive and tender or other vehicle,is represented by the Wheels andv axles 19, and receiving coils 20 in front of the Y I f first axle andnivheels areresonated by a condenser 21 and connected to the input circuit of .Y i

an amplilier TA, the output circuit ofV which is connected to one field Winding 22 of' the main car relay MR. Other coils 23 in the rear V phase and line phase currents or absence of either, in the usual Way.

In addition to the relay MR, another relay LR is connected to the output of the line phase amplifier LA, this relay LR being either 'of the single phase alternating current type, or, if an extra rectiicying tube is used, this relay may be a direct current sensitive relay of the tractive type.

Referring to Fig, 3, the gearing and associated devices diagrammatically illustrated are similar in many respects to that shown in my prior application, Ser. No. 38,132 filed duly 2, 1915. rlhe shaft 23 is operatively connected to an as-.e of the locoinotive or other vehicle by suitable means not shown and drives a speed responsive device SD, which is shown in a simplified and conventional manner as of the usual'centrifugal type, acting to move a collar 29, downward in opposition to a spring 30 as the speed increases and thereby rocking a s peed shaft 31, through a connecting arm 32, to different angular positions in accordance with the running speed. The speed shaft 31 is used to open and `close contacts throughout different rates of speed.

A typical speed contact '.unit is shown in F 3, and comprises an actuating sector 33 secured to the speed shaft31 and having its outer edge formed with two concentric curved portions of different radii, connected, connected by an inclined portion constituting an operating shoulder. A roller secured to a resilient or spring-pressed contact finger 34l bears against the edgeof the actuating sector; and in the form of speed contactv fingers shown in Fig. 3, the contact finger 34. is forced by the operating shoulder on the sector 33 ao'ainst a stationary insulated Contact 35,

indicated by an arrow, when the running speed is l5 miles per hour or less. It 'will' be evident that the edge of the contact'actuatmg actor 33 may be shaped to provide for the opening or closin of contacts throughout Vany desired range of speeds.

The car apparatus includes twov distance `element, operatingl shafts 36 and 37; but

since these elements are constructed substanfl tially the same, a description of one will suffice for the other, the same reference characters with distinguishing exponents being used. A worin 38 on the shaft 23 drives a gear 39, a shaft 40 va pinion 41, and a gear 42. A pinion 43, constantly in mesh with the gear 42, is carried by a'swinging arm 44 pivoted on the axis of said gear; and this pinion 43 moves into and out of mesh with a gear. 45 as the arm v4,4 is raised or lowered, said gear 45 having a mutilated or cut-away portion 46 for the purposehereinafter explained. The arm 44 is urgedfto vits upper position by a spring 47to bring the pinion 43 into mesh with the gear45 and is held in its lower position by a cam starter magnet HCS. The gear 4.5'is fastened to the distance-shaft 36 (and 451 is similarly fastened to 37) which is biased to a predetermined initial position shown by a spring 43, anchored at one end and connected at the other end to a short crank arm 49 fixed to said shaft.

The distance shaft 36 drives a permissive cam 50. A roller. on the upper end of a floating `lever 5l. engages the edge of this cam 50; and the lower end of this floating lever is pivotally connected to van arm 52 fixed on the speed shaft'. An intermediate point of the floating lever 51 is connected by a pivcted link 53 toan actuating sector 54 which is rocked by a spring 55 in a direction to press the roller on the lever 5l against the cam 50. This actuating sector 54 and its contacts 56 are constructed similar toV .those already described, and act to open the contacts when the'middle point of the floating lever assumes a predetermined position to the left. i'

The cam 50 is shaped, with regard to the angular movement ofthe associated parts, so that when moved gradually by the'car wheels, the contacts 56 open yat ldiiferent speeds for different locations of the train in the block in conformity with a speed distance curve of permissive speed such as the curve 57 Vshown in Fig. 1,'the way in which this result is obtained being explainedmore in detailin my prior application above mentioned. l f i V Each of the distance elements or shafts 36 and 3.7`is used to open or closecontacts at predetermined points of travel of the train. A typical distance contact is shown in Fig-,3, and comprises an actuating' cam disc 58 and a pair of contacts59 biased apart, said contact disc being provided with recesses and shoulders xtending over different arcuate portions of the disc, so as to open or close the contacts at the desired point in the rotation of the corresponding distance shaft.

In addition to the operating gearingfand contact units shown in F ig. 3, the car apparatusincludes a suitable brake control device. Since the particular brake applying means forms `no part of the present invention, la conventional form of electro-pneu matic valve EPV has been illustrated to facilitate explanation of the manner ofrcontrol of therbralreait being assumed that the automatic brakeapplying mechanism will be controlled by an electro-pneumatic valve and will be actuated whenever this valve is deenergized. -v y The car apparatus also includes anaclrnowledging contacter AC, which inthe form shown comprises ya push button or plunger 6l, urged by a spring 62 to the upper position shown, anc carrying insulated Contact discsl 63 and 64 arranged to engage stationary contacts shown conventionally by arrows. An armature 65 is fastened to this plunger 6l, andwhen the plunger is in its lower posif tion, .and a magnet 66 is energized, the

plunger'l will be held down against thev opposition of the spring, 62.` The magnet 66, however, is not strong enough to pull the plunger 61 down. For purposes more fully -x'plained hereinafter, an emergency non'- control contactor N is also provided; and in y the simplified Vform shown, this contactor comprises a simple push button or key?, inclosed within a locked or sealed casing indicated by the dash lines. The car apparatus Cit ILO

also includes any acknowledging relayAR, a non-control relay NC, a penalty relay PR, and suit-able cab signals or indicators. rlhese cab signals are shown for simplicity as consisting ol electric lamps ot different colors; but these signals may take any suitable forni, visual or audible, one construction preferred for ordinary uses comprising a lamp behind a glass screen'which causes letters or other Villustration and facilitate explanation.

distinctive insignia to stand out, plain or,

colored, when the lamp is lighted.

Fig.4 shows the electrical connections between the various devices of thecar apparatus; and in this circuit plan, various conventions have been adopted to simplify the The Contact lingers of the va 1ions relays are shown directly under the conventional illustration of the windings,ithe several lingers for each relay being connected by dash lines.

p Operation The car relay MR moves its contact lingers to one eXtreme position, shown in full linesr in Figs. 1 and 4, while the train is traveling in a clear block, shifts these contactsy to the opposite extreme position in a caution block, and permits these contact lingers to assume the biased vertical position in a danger block, this operation beingtypical of the three-position type of continuous inductive control system shown and requiring no further eX- vvplanation. The line phase relay LR is maintained energized, except atthe vdeadsections, throughout block signal territory, and is Vcle-energized only at approach to anV absolute stop signal.

Fig. 4 shows the parts and circuits of the car apparatus their normal initial condition corresponding to the movement ol the Vtrain in a clear block at some intermediate speed higher than the minimum speed, assumed to he 15 miles per hour, and lower than the maximum speed, assumed to be 60 miles per hour. In the normal condition of the car apparatus, the green or proceed cab signal G is energized and illuminated by a circuit which may be traced as olloivsz--Beginning at the positive bus 75, wire 86, linger 87 oli the relay MR and its normal contact, wires 88 and 89, finger 90 of relay NC and its back contact, wire 91, lamp Gr, and wire 92 to the negative bus 7 6. Y

' The cam starter magnet HCS is energized by a circuit which may be traced as lollows Beginning at the positive bus 7 5,

wire 86, linger 87 of relay MR and is normal contact, wires 88 and 93, cam starter maonet HCS, wire94, linger 95 of relay Alt anc its back contact, and wire 96 to the negative bus 76.

-f The other cam starter magnet LCS is energized by a circuit which may be traced as follows Beginning at the positivev bus 75, wire 97, linger 98 of relay MR and its normal Contact, wires 99, 100 and 101, cam starter magnet LCS, and wire 102 to the negative rlhe penalty relay PR is` normally ener-A gized by four circuits which may be traced as ollows:-Beginning at the positive bus n:

-wires 157 and 107 to wire 108;,linger 109 Lolf the relay PR and its front contact, wires and 111, winding of relay PR, and wires 112 and 113, and then in multiple; wire 114,

linger 1150i relay LR and its front contact, i and wire 116 to wire 117 or, wire 168, contacts 72 and wire 167 to wire 117 'speed-dis tance contacts 56,A and wire 118 to negative bus 76. v

The electro-pneumatic valve EPV is normally energized by two circuits as follows (1) Beginning at they positive bus 75, wires 120 and-121, distance contacts 73, wires 122, 123 and 124, linger 125 of relay 13R .and its front contact, wire 126, valve EPV, and wire 127 to the negative bus 76; (2) beginning at the positive bus 75, wires 120 and 121, conN tact 7 3, wires 122 and 164, Contact 74, wires 163Yand 165, baclr contact 160 of relay AR, wires 166 and 124, front contact 125 of relay PR, wire 126, winding of the E. P. V., wire 127 Vto the negative bus 76. rlhe seccnd en cuit just traced is, however, a moot circuitbccausethe 'functioning 0'contacts74 and produce no Vei'iect. as tar as the circuit in question is concerned, because these contacts are shunted by the wire. Y, Y

f Maxim/am speed limit'. While the train is traveling under a clear or proceed signal ina clear block, a predetermined maximum speed limit is imposed and the brakes are autcmati cally applied il the tr in exceeds this speed limit.V Referring to Fig. 3, with the permissive speed cam 50 in its initial position, il the running speed of the train exceeds a certain value, assumed to be 60 miles per hour, l

til lower end of the floating lever 51 is moved so far to the left as to cause. opening of the contacts 56 which break Vthe energizing circuit for the penalty relay PR. Upon de-energization of the penalty relay PB, its front Contact i icc lio

125 opens and deeenergizesthe valve EPV, thereby automatically applying the brakes. The penalty relay PR can not again be enen Vgized `until the train has been brought substantially to a stop to close the speed contacts 69 whereupon a pick up circuit for the relay PR is established as followstBeginningat the positive bus 75, wires 130 and 131,'two mile per hour speed contacts 68--69, wire 132, linger 133 of relay LR and its front contact, Wires 134 and 111, winding of relay PR, and Wires 112, 113 and 114 through contact 115 of relay LR,'wires 116 and 117, speed distance contacts 56 and wire 118 to the negative bus 76 as in the normal'closed energizing circuitfor the relay PR above traced. Y

In the particular arrangement shown, therefore, the train is brought to a stop whenever the maximum speed limit is exceeded, thereby in effect penalizing the engineer for exceeding the speed limit. This penalty, however, is optional; it should also be understood that the system preferably includes a suit-able warning signal which is given when the speed of the train approaches the-maximum speed limit.

' Caution Hoda-Men the train enters a caution block, or passesa corresponding control point, the contact fingers of the main car relay MR are reversed, extinguishing the lamp G and lighting the lamp Y, (wire 135 and reverse contact of finger 87), and also deenergizing the starter magnet HCS, while maintaining the cam starter magnet LCS' energized (through wire 136 and reverse contact of linger 93).. rllhe de-energization of the cani starter magnet HCS connects the distance shaft 36 to the car wheels, and in addition to starting the gradual movement of the permissive speed cam 50, also rotates the actuating discs of the distance contact units 59 and 710. Referring to Fig. 1, after` the train has advanced a short distance into the caution block, say 200 feet, which is longer than the lon-gest dead-section distance encountered on the. railway, the contacts close, as ind1- cated by the change of the line 7 O in Fig. 1.

from 'dotted to a solid line.v The closuretof these contacts 70 establishes a circuit for en ergizing the acknowledging v'signal as follows Beginning at the positive bus 75, wires 141, 142 and 143, contacts 70, wires 144 and 145, contact 64 of the contactor AC, wire 146,"acknowledging signal B, and wire 147 to the negative bus 76.

The magnet 66 is also energized over wires 148 and 149.- The sounding of the acknowledging signal B isa warning to the engineer to `oi'icrate the acknowledging contactor; and assuming that the engineer is vigilant 'does acknowledge by moving the plunger 6l 'to its lower position, the opening of the contacts 64 stops the acknowledging signal, and the closing of the contacts 63 setsup an energizing circuit forthe acknowledging relay AR as follows:-Beginning at-the positive bus wires 141 and 150, contact 63 of acknowledging contacter AC, now Y closed,

.wire 151, relay AR, and wire 152 to the negative bus 76.r I

The plunger 61 is held in its lower position by the magnet 66. After a further distance of travel, suiiicient to afford reasonable time for the engineer to acknowledge, the'contacts 59 open, as indicated by the line 59, in F ig. 1. The opening of these vcontacts 59 makes a break in the normal energizing stick circuit 'for the penalty relaylR; but since the engineer is assu-med'to have acknowledged, the front contact 154 ot' the acknowledging relay AR is closed, supplying current from the bus 75 to the wire 108 over wires 153 and 155 in spite of the .opening of the contacts 59, thereby maintaining the penalty relay energized.

the engineer fails to acknowledge, the opening of the contacts 59 de-energizesthe penalty relay PR'which in turn de-energizes the valve EPV thereby applying the brakes, and maintaining them applied until the train isbrought to a stop as indicated by the curve 78 inl* 1, whereupon the penalty relay is re-energized by the Closure of the speed contacts 69 in the same way as previously eX- plained. But regardless of acknowledgement, speed lrestriction is enforced, in accordance with: speed distance curve 57, by the can-i 54.

vThe contacts 59 remain open for onlyy a V short distance of travel, (see Fig. l), and after closure thereof, the contacts 70 open, Cle-energizing the magnetv66 and releasing the plunger 61 which is restored by the spring 62 to its'upper normal position.

y,As the train advances throughthecaution block, the permissive speed cam 50 is graduallyturned and enforces successively lower speed limits.y If at any point in the travel of the train its running speed exceeds the permissive speed, tlie contacts 56' open, de-energizing the penalty relay PR and in turn the valve EPV, applying the brakes and maintaining the brakes applied until the train is brought substantially to a stop and the penalty relay PR is again. energized. YConsequently, thek engineer must maintain the speed of his train below the permissive speed ycurve 57 shown in F ig. 1,r orelse the brakes are automatically applied, and as a penalty,

.the train must be stopped. before the brakes gy,

can be released.

\ After the train has advanced to a predetermined point, indicated by a break in the lines 59. and 70,l the contacts 70 are again closed, and again the contacts 59 open, compeiling acknowledgment lin the samev way as previously explained. The point'in ythe block, at which thewcontacts 59 open isi pref- Y erably braking vdistance for the minimum speed from the exitend of the block, so that if CII the engineer is incapacitated, or *forA any other reason fails to'acknowledge, the resultant brake application will stopotlie train be'- 'lfore the train reaches the exit end ofthe block, as indicated by the curve 7 6 in Fig. l.

lAs shown, the permissive speedcam is asmissive speed cam 50 to assume its minimum` speed position at, or a smalldistance in the rear of, the point at which the contacts 59 open.Y

It the block should change from a caution Vblock ,to a clear block at anytime, the contact linger 87Y ofthe main car relay MR assumes the normal position (shown by a heavy line) changing the cab signal indicat: on 'from caution to proceed. land re-energiz-v .Y ing the cam starter magnet iiCS. vThe shait 36 is returnedto its initial position by the spring 48, and during such return movementV oit the shaft 86, the contacts 59 are opened momentarily; and while the penalty relay PR may be made sufciently slow acting to avoid its improper operation by suclrmomentary opening of the contacts 59, it is pre'lerred to provide an auxiliary circuit, including' wire 157 and'normal contact and linger 156 of the relayMR to supply energy to the wire 10T and to maintain the penalty relay PR energized in spite of the opening of the contacts 59.

In order thatthe ingineer may not be able to defeat the objects of the invention by permanently fastening or holding down the acknowledging contactor AC, the finger 95 and yits back contact of the iacknowledgingrelay AR, are included in the energizing circuit-for the cam starter magnet HCS, so that, if the engineer should keep his acknowledging contact AC depressed andthe relay AR energized, the cam shaft 36 is run down and maintained in its minimum speed position. Consequently, the engineer will not fasten down the acknowledgingcontactor AG in order to V Yavoid acknowledging the caution indication,

because by so doing he restricts thespeed to a minimum. Y

Danger loda-As the train passes from a caution to a danger block, the shaft is in its extreme position and is held there, the pinion 43 rotating idly in the mutilated portion 46 of the gear45. As the train passes into the danger block, the car relay MR is deenergized and itsl .contact lingers assume the neutral ormiddle position, de-energizing the cam starter magnet LCS and starting in Vrotation the distance shaft 37. Referring to Fig. l, after a short distance of travel of the train, longerfthan deadsection distance, the contacts` 7l closel giving the acknowledgment re uired near the end oi the irecedin C of l5 miles per hourl ,t

cuit for the valve E?? un ing signal B and energizing the magnet 66'. After a furtherdistance or travel, the contacts 591 and 72 open, and unless the engineer has acknowledged and brought about closure of the front contactll of the acknowledgi ing relay AR, the penalty rela-yl PR is de? energized, with thesaine result previously pointed out. rllie purpose of the Contact 72 is pointed out under `the heading absolute stop. y 1

This acknowledgment just beyond theentrance to a danger block is to some degree superfluous for the iirst stop signal, inasmuch as it merely supplements, the acknowledgcaution block. rlhe acknowledgment j ust described, however, is .desirable to assureacveoinetiinerbetoi'e the Ytrack ahead becomes clear to permit the Ytrain to advance by the stop signal. Consequently, after a train has passed one stop signal and entered into a danger block, except ifor the case oit interlocked territory as for example, block l oi' Fig. 2, it cannot pass a second stop signal until the block it is in, formerly a danger block, has for a. short distance of travel at least, changed to a caution block. During this change to a .caution block, he cani starter magnet LCS is re-energized, restoring the distance slia'l't 37 to its initial position; and as the train passes the second stopesignal and advances into a danger block again, this distance shaft 37 is again set into oper tion and the opening of its contacts 591, forces acknowledgment. During the return of 'the shaft 3'?, the pen alty relay PR is prevented from dropping upon momentary opening ofthe contacts 59L point where the' f breaking the normal the valve EPV, lieretotore*i` ing the energizationot '-1 pendent uponr the su ,l (closed only at .and bolo o lthe Y and the nger o Y 125 AR and its back con 'these e n tions being'traced as the positive bus 75,1 Y muin'speed contactsA 34u35, wire 162, vand contacts 74 and wires 16a and 123 to th thence either along wire it?? through i stance e wire 121i, or through wire 165, Vlinger lGOof relay AR and its back contact, and wire 166 tothe wire 124, and thence through the front contact 125 ot' the penalty relay' PR, wire 126, valve EPV, and wire 127 to. the negative bus 76.

AOn account ot this circuit arrangement, after the train has traveled a short distance into a dangeil block, the valve HPV is automatically de-eneigi.Zed whenever the running speed of the train exceeds the selected minimumv speed limit; but since the minimum speed limit in question is already enforced by the cam 5() in its extreme position, the control of the valve EPV provided bythe mini* mum speed contacts 3er-35 lis merely inci dental tothe desired control through a danger block and is employed more particularly for protectionagainst open switchesand the like, as Will-.presently be described.

The multiple branches inthe circuit Jfor the valve EPV just traced through the distance contacts 74 and back contact 160 of the relay AR are provided in order to protect the acknowledging contactor AG against abuse while the train is in a danger block. The contacts 74. open after a distance of travel. Sullicient to complete the acknowledging operation and after the relay AR has become de energized. lit the engineer, however, instead of releasing the acknowledging contacter AC and permitting it to return to normal, should attempt to vavoid the acknowledgment ot the -neXt stop signal by holding or fastening down the acknowledging contacter AC. then the back oontact'l() ofthe relay AR remains open, whereupon the valve EPV is 'de-enci1` gizedy upon opening' of the distance contacts 74.

Open sevizio/laad siding protection-lt a switch should be opened ahead of a trainin the same block, or a rail break, the car relay at once assumes its cle-energized position. Similarly, it a train passes 'from a sidingf into an occupied block on the main track, die main car relay MR, ii energized, is at once decneigized, and iit do-cnergized, remains in its cle-energized condition.

Referring to ll, whenever the car relay MR assumes its cle-energizedposition', the

,cam starter magnet LCS is de-energized; and

after a short distance of travel to take care of dead-sections, the distance contacts open, breaking the normally closedsliunt around the' minimum speed contacts-B,

and reifnlering` these minimum speed contacts.

effective to control the valve EPV, above described, so that it the speed otthe train at thistime is more than the minimum speed off Ii miles per hour, the valve EPV is cle-ener? gized and the .brakesv applied.` Accordingly, whenever the main car relay MR assumes -its ale-energized position., the minimum speed limit is at once set up after a very short distance of travel, say 150 feet, and it is not necessary to run down the. permissive speed camy 50 to its minimum speed position..

Hence, when a train comes out from a siding onto a main track into a danger or occupied block, the minimum speed limit is at once iniposed, irrespective of the position ofthe permissive speed cani, which may be in difierent positions depending on how the train` solute stop controhit is desirable to compel 3 an approaching train to reduce'its speed, and at ornear the absolute signal or correspondling point of control, apply the brakes auto-A inatically irrespective of the speed ot the train as it passes such signal or control point,

.such brake application being beyond the power of the engineer to prevent, by acknowledge ment or otherwise.

Referring to Fig. 2, the signal ZA at the exit end of the block K is assumed to be an absolute stop signal which is controlled in accordance with established practice, wholly manually, or partly manually and partly automatically. Since the particular means that maybe employed to control tliisabsolute stop signal ZA may take various forms and is not material to the present invention, no attempt has been made to illustrate any particular organization of circuits andy devicesl for providing the required control 'for this signal. ln the block K, in tli-e rear of the absolute stop signal ZA, the track phase'or loop circuit cui`- rent is supplied to the track rails in the same way as in block signal territory, as shown and described'in connection With Fig. 1. The line E phase or simplex circuit current is controlled in diiierent ways dependent upon the posi-y tion of the signal ZA. A circuitcontrollerl, assumed to be operated by movement of the signal ZA, Vor by its controlling lever, or by equivalent means, is in the position shown with the signal ZA in its stop position, supplying'lin-e phase or simplex circuit -current between the resistances 72 and lll of the-block l only; Whereas with this vsignal ZA in its caution or clear position (assuming a. 3-posi`-V spect to the track phase current. l/Vith ythe 5 een i signal ZA in the stop position shown, the pole changing circuit controller 16 is in the position shown and reverses .the instantaneous polarity of the line phase current, so as to cause the car relay on a train traveling in the block K to assume its reverse position. With the signal ZA in the caution or clear position, the circuit controller 16 assumes its other position, providing normal polarity of line phase current. Y

Assuming the signal ZA to be in its stop position, ,when a following train enters the block K, its car relay MR is reversed with the same effect as previouslyv explained. If the engineer fails to acknowledge, the brakes are applied and the train brought to a stop, as

indicated by the curve 7 8.; and Ieven if the engineer does acknowledge, he is obliged to keep f the yrunning speed of his train at all times below the permissive speed curve 57, otherwise the brakes are automatically applied. When the locomotive passes the resistance 14,

. the main car relay MR `assumes its cle-,energized position, Yand also the line phase relay LR on the car is dei-energized, since yfrom the i contacts 59 and591, and also contacts 70 and 71, to be shifted at about the same time. The operation of these contacts gives the acknowledging signal and applies the brakes'if the engineer fails to acknowledge, the same as previously explained. v

So far considered the ooeration u on a3- Y. v i p proaching the absolute stop signal ZA is the same as that occurring upon the approach to a permissive stop signal in block signal ter-V ritory. ln the case of the absolutestop signal,'however, the line phase relay LR is deenergized, releasing its contact fingers and 133 to open their front contacts. VThe opening of the vfront contact of the ingerl?) interrupts the pick-up'circuit for *thepenalt-yV relay PR which includes the low speed contacts 68 and @9,so Ythat once the relay PR is cle-energized toapply'thev brakes, it cannot again be energized to permit release of the brakes even though the train is brought to a stop. AtV a predetermined point near the exit end of the block l, preferably andv assumed tofhe braking distance for the minimum speed'froin the actualexit end of this block, the contacts 72 are opened, as indicated inlfig.V 2, breaking theshunt (including wires 167 and 168) around the ContactV linger 115 andfront contact of the relay LB.

lplained.

Conse uentl if a train advances be ond the1 point at which the contacts 72 are open, thek relay LR being cle-energized, the penalty relayy is cle-energized, and the brakes applied. The point at which the contacts 72 open, therefore, becomes the point of absolute stop control in the event the line phase relay LitV is also cle-energized. As shown, this point is a short distance in the rear of the signal ZA; but if it is desiredto permit the locomotive to advance ali tne way up to the signal ZA,

eig; 4

as ordinarily done, the signal ZAinay be lo- The train'must stop at the signalZA in its stop position until this signal is cleared, whereupon the circuit controller 15 is shifted to supply line phase or simplen`T current throughout the length of the blockV l and energize the relay LR.V rlhe re-energization Vof the relay permits restoration of the penal- Sil ty relay PR and release of thehrakes.` lf

the signal ZA is cleared. to the caution position, the cam starter magnet LCS only isv energized, and the distance shaft 37 restored to the normal position, the minimum speed limit being maintained during the further advance of the train on account of the cam 50 being in its minimum speed position. lf, however, the signal ZA is cleared to the proceed position, the car relay MR is restored to its normal position, both of the cam starter magnets LCS and HCS are energized, and

the car apparatus is restored to the normal' condition in the manner previously eX- ln conformitywith recognized interlocking practice, it may be desired to einploy a call-on signal in conjunction with the signal ZA and permit a train to advance beyond the'signal ZA in its stop position at vrestricted speed. This is easily accomplished by making provision for shifting the circuit controller 15 upon operation of the call-on signal, so that the train may Yadvance without absolute stop control past the signal ZA. `Ylt will be evident that? other adaptations and inodilications may be made to incorporate,

withthe absolute stop train control arrangement shown, other features of interlocking` practice. Y Y .y i,

Nou--Uoutrol territory-lt :will be evident that in the system of this invention, current must be applied to the track rails topermit f a train to proceed. ln thepractical application of. a train control system to railroads,

however, certain portions of track, suchfas sidings, branch lines, and the like,mayrnot be equipped toprovideV train Vcontrol, current, Y

such portions of track constituting non-conlib trol territory. Iy'n order to permit the train to travel over such non-'control territory,

special means is provided to permit cut-out the engineer is supposed to operate the ac-A knowledging contactor AC, being guided by a marker along the track or equivalent means, thereby establishing a circuit for energizing the non-control relay NC Which may be `traced as follows z-Beginning at the positive bus 75, Wire 170, linger 171 of relay MR in the normal position, Wires 172 and 173, finger 174 and its front contact of the ac'- knowledging relay AR, Wires 175 and 17 6, relay NC and Wire 177 to the other bus 7 6.

As the train proceeds into non-control territory, the relay MR is Cle-energized, thereby establishing a stick circuit for the relay NC, NC not dropping While finger 171 moves from normal to neutral positions, as follows Beginning at the positive bus 7 5, Wire 170, linger 171 of relay MR and its neutral contact, Wire 178, finger 179 of relay NC and its front contact, Wires 180, 181 and 17 6 relay NC and Wire 177 to the other bus 76. The contact AC is then released to cle-energize the AR relay.

Thus, the relay NC is energized, due to acknowledgment, upon entrance to the non-control territory, and is maintained energized, by being stuck up, While the traintravels through this non-control territory. The relay NG, while energized, performs several functions. The attraction of its finger 179 interrupts the circuit through the danger or low speed lamp or indicator R, and in addition to establishing the stick circuit for the relay NC,.supplies current to energize a lamp or indicator 7W, which serves to remind the engineer that he is running in non-control territory. The attraction of the finger 90 establishes a circuit, including Wires 130, 183 and 184, for energizing the cam starter magnet HCS, and the attraction of the linger 18.2 establishes a similar circuit, includingivires 185 and' 186, for energizing the cam starter magnet LCS. The attraction ofthe finger 188 establishes a connection from one terminal of the penalty relay PR over Wires 112, 187 and 189 to the negative bus 76, so 'as to maintain the relay PR energized in spitel of the ropening of the speed-distance contacts 56.

When the train re-enters regular train control territory, the car relay MR is energized, either normal or reverse, preferably the latter by the regular train control current, or by current especially supplied irrespective of traflic conditions over a short section at the entrance to train control territory; and when the car relay is energized, the stick circuit for the relay NC is interrupted and this relay is deenergized, reinstating regular train control. Y

f In order to permit the trainto proceed in case of a sudden failure of power, or under other conditions Where the NC relay has not been energized in the usual Way, an emergency contactor in the form of a push button 67 is provided to permit energization of the relay NC. rlhis push button 67 is safeguarded in somev appropriate manner, as by being locked or sealed, or provided With a counter, so that it cannot be abused by the engineer Without detection.

Various adaptations or modifications may be made inthe particular embodiment of the invention shown. The acknowledgment at the cauti/on signal may 'be omitted', by leaving od the notches on the actuator cams operating the contacts 59 and 7 O shortly after the cam shaft 36 starts. rlhe penalty for eX- ceeding the permissive speed limit may be omitted by including the speed-distance contacts 56 directly intie energizing circuit for the valve EPV, rather than in the circuit for the penalty relay PR.y Similarly, the Contact finger 115 of the relay LR, and the distance contacts 7 2', may be -included directly in the energizing circuit for the valve BPV rather than in the circuit for the penalty relay In short, the particular circuit organization shovvn may be adapted to omit or modify some of the functions described.

The modalisation of Fig. 5.-,Revievving the general organization and operation of the embodiment of the invention hereinbefore discussed, one feature relates to the provision of means for automatically applying the y brakes at a predetermined point in therear' acknowledgment ofthe stop signal, this ar-l rangement requiring starting of the cam shaft 36 at a-predetermined run-out distance inthe rear of the acknowledging point. In the modification of Fig. 5, the acknowledgment for the stop signal is 'obtained by de-energiz- .Y

ing the main car relay MR at a predetermined point, conveniently referred to as the fB point, at ay distance in the rear of the signal sufficient-to cover the dead-section distance and braking distance for the minimum speed.

Y ting off the track phase or loop circuit current for a short distance near the exit end of each caution block. Y

Referring to Fig. V5, the equipment for a block N, assumed to be next in the rear of an .absolute stop signal ZA, has been shown complete together with the equipment for a portion of an adjacent block M. Although many of the parts are similar to those shown in Fig. 1, for convenience different reference numbers areY employed. Each block is made up of two track sections, the block N having insulated oini's 190 at the point B forming a short track section i a at the exit end of the full block. The first or rear section of each block, between the entrance and the point B, has a track relay 191 and a track battery 192, and is permanently suppliedl with track phase or loop circuit train control current by a transformer 193, having its secondary in series with the track battery 192and its primary energized byV a line transformer-194i. The short section at the exit end of each block, from the point B to the exit end of the o block, is equipped with a track relay 195 and a track battery 196. A transformer 197 has its secondary in series with the'track battery 196 and its primary energized from a line transformer 198, this primary circuit also including the contact finger 199 and front conn tact of a line relay 200. This line relay 200 has an energizing circuit which includes front contacts 201 and 202 of the two track relays 191 and 195 of the next block in advance. Line phase current is constantly supplied to the rear section of the block between resist- 206 and 207 operated by the correspondingV line relay 200. Y In automatic block signal territory, represented by the block M, line phaseV current is permanently supplied to the second or advance section of each block (section Ma) betweenthe resistances 20S and 209 from a line transformer 210. VIn the block N in the rear Aof the absolute stop signal ZA,however, the

line phase current for the section Na, between the resistances 208 and 209, is controlled by a `circuit controller 211, which in this instance is assumed to be associated with the interi s locked lever controlling the signal ZA.

The car apparatus for Fig. 5 may .be the same asthat shown in Fig. ll, except that the projections and recesses on the actuators for the distance contacts 59 and 70, which result in the operation of these contacts when the cam shaftBG nearly reaches its extreme posi- `tion are omitted.

Referring to Fig. 5, when a train enters ra caution block in block signal. territory, the

saine operation hereinbefore described takes-m place to require the engineer to acknowledge the caution signal; and at 'the point B in this block the distance shaft 37'is started and through the operation of contacts 591 and Z1 requires the engineer to acknowledgethe danger signal. 1n Fig. 5, however, there is only one acknovvledginent for the first stop signal required, that due to the opening of the contacts 591 after a travel beyond the point B of dead-section distance.

l/Vith the absolute stop signal ZA in the stop position, a train traveling through the block ifi/l is required to `acknowledge the caution signal, reduce speed, and acknowledge the stop signal the saine way as in the Since the sig-4 rangeinent shown in Fig. 1. nal ZA is in the sto p positionand the circuit controller 211 open, there is no line phase current` for the sectionN, and the vrelay LB is cle-energized. so that if the train advarices beyond the point where the distance contacts 72 open, an absolute stopv is en- V forced. l

rllhe ii'iocification of Fig. 5 provides for enforcement or acknowledgment of succes-- sive stop signals butin a somewhat different manner than in the arrangement of Fig. 1. 1n Fig. 1, as previously eXplained, succeeding stop signals are acknowledged at a point dead-section distance beyond the Vsignal icc where the distance contacts 591 open (see y Fig. l) whereas in Figo, the acknowledgment of each stop signal, whether the first or a succeeding stop sigi'ial, taires place at the saine point, namely, dead-section. Vdistance beyond the point B in each block. In the arrangementsliown in Fig.. 5, when a train passes from a caution block into Va danger block, both of the shafts 36 and 37 aren-i the ultimate operated position. 1f the forward train in the danger or occupied'block is beyond the point .5, as soon as the fol'- lovving train passes into tiiisdanger or occuy pied block, the main car relay MB is energized to move its fingers to the reverse position, restoring the shaft 37 to' its initial position, but'leaving the shai S6V in its run-out ,u posit-ion to'rnaintain the continuing minimum speed limit. /hen the foilowi ng 'train passes the point B, and the next signal in advance is at stop, or the intervening sectionioccupied by another train ahead, the inain car relay is again ele-energized, starting rotation of the shaft' and requiring the engineer to acknowledge. 1f it should happen that, when thefollowing train enterstlie danger or occupied block, the forward 'train is in therear of the point-B, then the main car relay remains fle-energized. VAt soine point intlie travel'of the two trains, however, the car Vio 51,765,3.a2iA

relay MR on the following t-rain is energized i'eversely, since there is some instant trative purposes; and "itshould bey under-l stood that various changes, additions, modifications, and adaptations may be made Without departing from the invention.

`What I claim is 1. Car-carried apparatus for automatic train control systems of the type in which a ar-carried relay is maintained energized in response'to current flowing in suitable trackway circuits under clear traffic conditions ahead, such circuits extending through the whole trackway except Vfor short distance intervals at dead sections, a brake setting device, 4a speed responsive device, a distance device normally in its inactive condition but` initiated upon al cycle of operation when traffic conditions change from clear to caution as manifested by said relay, means governed by said distance device for gradually-setting up decreasing speed limits and for actuating said brake setting device if ,the actual speed of the vehicle exceeds such permissive speed, and another distance device normally in an inactive condition and initiated when the trainenters a danger zone, said another distance device abruptly setting up a'predetermined low speed limit when the train has traveled more than the maximum dead section distance after this distance device has been initiated.

2. Car-carried apparatus for automatic traincontrol systems of the type in which a car-carried relay is maintained energized ink response tocurrent flowing in suitable trackway circuits under clear traffic conditions ahead, such circuits extending through the whole trackway except for short distances at deadv sections, a delayed action device normally held in an inactiveA condition by a three-position relay which is maintained energized by currents flowing in said'trackway circuits, single element relay normally maintained energized in response to currents flowing in one of said trackway circuits, and means for stopping the train regardless of the speed thereof if the single-elementrelay is in adeenergized position when saiddelayed action device has changed a predetermined degree from normal.- v, f

3. Car-carried. apparatus for automatic train control systems of the type in which a car-carried relay is maintained energized in response to current fiowinginisuitable trackway circuits under clear traffic c onditions ahead, -siiclrV circuitsv extending i through the whole traclrway except for short distances at dead sections, a delayed action device-norergized by currents flowing in said trackway maintained energized in response to currents flowing in one of said trackway circuits, andA means effecting an automatic brake applica tio'nif the engineer does not manifestrhis vigilance if a' train travels more than a predetermined distance with said'three-position relay deenergized, and means for effecting an automatic application of the brakes if the rtrain travels a' predetermined distance 'with boththe three-position' relay and the single element relay deene'rg'ized regardless of whether ornot the engineer Vmanifests his vigilance.v

4. Car-carried apparatus for automatic train control systems of the 'type inwhich a -mallyiheld in an-inactive condition by a` three-position relay which is maintained .en-

circuits, a single element relay normallyv car-carried' relay is maintained energized in f vresponseto current flowing in Asuitabletrackway circuitsunder' clear traliic conditions ahead, such circuits extending through the -whole trackway except for short distances at deadsections, a delayed action device normally heldin an inactive condition by a three-position relay-which is maintained Aenergized by currents flowing insaid trackway circuits, a single elementrelay normally maintained energized in response tocurrents flowing in one of said .trackway circuits, and means'for effecting an automatic brake application if thev engineer does not manifest his vigilancel if the train travels a predetermined .distance with said three-position relay in the reversed or the de-energized position, and means forv effecting anv automatic brakeapplication regardless of the engineers manifestation of his vigilance'if` said train travels said predeterminedrdistance with the single lelement relay deenergized.

5. Car-carried apparatus for automatictrain control system ofthe continuous inductive three lpositiontype in which the trackway is provided with circuits for conducting trainlcontrol current at all ypoints except for short distances atfdead sections comprising, i'

a permissive speed device normally in its maximum permissive speedcondition which if initiated gradually sets up Amore restrictive permissivespeed limits in accordance with the progress of the train along the'track and whi'ch'is initiated upon entrance of the train into caution territory, an actual speed device for ascertaining the speed at which the car is traveling, a brakesetting' device,a delayed action device normally in inactive condition' and initiated upon the entrance of the train into danger territory and which sets up a minimum speed limit vwhen'zthe train has traveled more than the maximum dead section distance, and' means for automatically actuating said brake setting device it the actual speedis higher than the lowest permissive speed set up by either-the permissive speed device or the delayed action device.

V6; Car-carried apparatus for automatic train control systems of the continuous inductive ,three-position type ,in which the trackway is provided with circuits for conducting train control current at all points except for short distances at deadsections comprising,.a permissive speed'device normally in its maximum premissive speed condition which if initiated gradually sets up f more restrictive permissive speed limits in accordance with Vthe progress of the train along the track `and which is initiated upon entrance of the train into caution territory, an

' actual speed device for ascertaining the speed at which the car is traveling, a brake setting device, a delayed action device normally in inactive condition and initiated upon the entrance of the train into danger territory and which sets up a minimum speed limit when the train has traveled more'than the maxi-V mumrdead section distance, means for automatically actuating said brake setting device if the actual speed exceeds the lowest permissive speed set up by either the permissive speedV device or the delayed action device, and other means for automaticallyV actuating said brake setting device under predetermined conditions ahead regardless 'of thespeed of the train.

7, Car-carried apparatus for automatic train control systems of theftype in which` a Vcar-carried relay is maintained energized in responsel to current flowing in suitable track- Y way 'circuits' under clear tralfic conditions ahead, such circuits extending through the whole trackwayexcept for short distances at dead sections, a three-position'relay adapted to assume a position dependent onthe chai'- acter of the Lcurrent iiowing in a plurality of trackway circuits, a single element relay de- Y pendent for its energization upon the 'low'ot' current in one of said trackway means for applying the brakes of the train 'if the train has traveled aV predetermined distance with` the three-position relay ,deenergized and the rsingle element relayr'is in its deenergized position.

V8.v An automatic tiaincontrol systein'ot the three-position continuous inductive type comprising; a trackway having Yalternating current flowing in suitable circuits located along the same throughout train control tei'- ritory except for short distances at points designated deadsections 'and ,of car-carried apparatus including, a permissive speed device normally assuming a maximum permissive speed condition which is initiated upon the Ventrance of the train into ,cautionl territory and which if initiated #gradually Y sets up lower permissive speed limits in accordance upon entranceoi the train into danger circuits and with vthev progress lof the train Yalong the track, a speed device, abrakesetting device acting on the usual air brake system, a delayed action device which is initiated territory and, means V'or actuating said brake setting device if the speed of the train as manifested vby said speed responsive device is higher than the lowest permissive speed set up by said permissive speed device and said delayed action device.

9. An automatic train control system coinprising means partly on the vehicle and part- Y ly along the trackway ytor .continuously transmitting influences corresponding to trailic conditionsvahead to the vehicle, car-carried apparatus comprising means responsive to said iniuences for manifesting said traiiic conditions ahead, a delayed action device,

delayed in accordance with the progress of the vehicle along the trackway and initiated upon the manifestation of adverse traiTic ccnditions ahead, an acknowledging device havin an active and an inactive Josition means for eiiect-ing an automatic brake application ii the acknowledging device does not assume its active position when said delayed action device has changed a predetermined degree from normal and for eii'ecting an autolayed in accordance with the progress of the f vehicle along the trackway and initiated upon the manifestation ci adverse traiiic conditions ahead, .an acknowledging device having an active Yand inactive position, means for eiftecting an automatic brake application if the acknowledging device does not assume lits active 4position when said delayed action device has changed a predetermined degree from normal and for effecting an automatic brake application if said acknowledging device does Ynot assume its inactive 'position when saiddelayedaction device has `changed a larger degree'from normal.V

' 1l. An automatic train control system comi prising, means partly onthe vehicle and partl Vly along the tracli'way for manifesting on the vehicle conditions of tra-mc existing ahead ot the vehicle, afdelayed actionV device nor- *inally maintained inactive which if initiated changes in accordance with the progress of the vehicle along the trackway, and which it changedto a predetermined extent sets up a low permissive speed'liinit which theV i vehicle cannot Vexceed without incurring an automatic brake application, an acknowledging devicehaving an active and an inactive position, and which is normally in its inactive position, mea-ns for effecting an automatic brake application regardless of the speed of the train if the acknowledging device is not in its active position When the delayedV action device has changed to a predeter mined extent, andl means for effecting an automatic brake application if the acknowledging device is not in its inactive posi* tion When said delayed action device has changed to a slightly greater extent.

12. In an automatic train control system, a three-position relay on the vehicle controlled in accordance with trailc conditions ahead by means of a plurality of trackWay circuits, a two-position car relay controlled by one of said trackWay circuits, said track- Way circuits being energized in accordance With trallic conditions ahead, means controlled by said three-position relay for imposing increasingly restrictive speed limits under certain unfavorable traiiic conditions ahead, and means controlled by said two-position relay for imposing an automatic brake application to bring the vehicle substantially to a stop under certain other unfavorable traiic conditions ahead.

13. In a train control system, car-carried apparatus, comprising, a train control device, means initiated by track-Way influences for imposing a tapered speed limit on thev train, a'second means initiated by diii'erent track-Way influences and effective after a moment of delay to abruptly impose a predetermined fixed lovv speed limit on the train, and means for initiating the train control device if the train speed exceeds said speed limits.

14. Car-carried apparatus for automatic train control systems of the type in which a car-carried relay is maintained energized in response to flow of track-Way current flowing under clear traflic conditions ahead, extending through the entire track-Way except for shortv distances at dead sections, a first relay adapted to assume a position depending on the instantaneous relative polarity of the y currentsflovving in the track-Way, a second relay depending for its energization upon the flow of current in said track-Way, and means for applying the brakes of the train after the train has traveled a predetermined distance With the first relay de-energized if the second relay is in its deenergized condition.

In testimony whereof I affix my signature.

' WINTHROP K. HOWE. 

